This was inspired by the P-82 “Twin Mustang”, and the result is a rather bizarre creation which would nevertheless appear plausible for Germany during the late stages of WWII. Actually, Arado’s real paper project E.530 looked very similar to this creation, but it was a bigger aircraft and intended as a fast bomber.
Other Zwilling designs even entered the hardware stage or were very concrete: the He 111 Z bomber was built and used mainly as a glider tug, the Bf 109 Z and Me 609 were derivatives of their respective normal ancestors, there was even a Do 335 with two fuselages as a long range reconnaissance aircraft on the drawing board!